Analyst Update: Clovis Oncology Inc, Calithera Biosciences Inc, and Gilead Sciences, Inc.

Analysts are weighing in on biotech stocks Clovis Oncology Inc (NASDAQ:CLVS), Calithera Biosciences Inc (NASDAQ:CALA), and Gilead Sciences, Inc. (NASDAQ:GILD). Here's a quick roundup of today's brokerage notes on CLVS, CALA, and GILD.

• CLVS is 4.5% lower at $30.86, after Chardan Capital Markets initiated coverage on the stock with a "sell" rating and a $15 price target -- a discount of more than 50% to the equity's current value. An analyst at the firm cited "considerable risks" surrounding the company's ovarian cancer treatment, rucaparib, which is under priority review by the U.S. Food and Drug Administration (FDA). Specifically, he noted the drug "does not appear to show a clinical benefit over existing therapies." Traders appear to agree with this pessimistic outlook. At the moment, 12.7 million shares, or roughly 70% of Clovis Oncology Inc's available float, is wrapped up in short interest -- following an increase of 29% over the last two reporting periods, and marking a new record high.

• CALA received a fresh "sell" rating and $1 price target from Citigroup, sending the shares plummeting 21.2% to $2.33 -- just off their new all-time low of $2.25, touched earlier. According to an analyst at the brokerage firm, Calithera Biosciences Inc lacks meaningful catalysts, and the company's spending points to the need for a partnership or fundraising to continue its current programs through the first half of 2017. CALA has been on a long downtrend since topping out north of $33 in December 2014 -- less than three months after the stock began trading publicly. The shares have shed nearly 70%% of their value in 2016 alone, so it's hardly surprising that short interest is elevated. These bearish bets currently account for 12.4% of the stock's total float, or 8.5 sessions' worth of trading, at CALA's average daily volume.

• Jefferies raised its price target on GILD by $2 to $95, saying, "we believe the Street underappreciated the impressiveness of" the firm's Phase 2 trial data released last week. Gilead Sciences, Inc. stock is up 0.4% to $74.43 today, but still sits on a 31.5% year-over-year loss, after tapping a two-year low of $72.21 less than two weeks ago. These technical woes haven't dampened options traders' appetites for bullish bets, however. At the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX), GILD holds a 10-day call/put volume ratio of 2.64 -- higher than 75% of all readings taken in the past year.